The present invention broadly relates to a method of grinding gear teeth and, more specifically, pertains to a new and improved method for controlling the magnitude and position of the grinding stroke of a gear tooth flank grinding machine operating on the indexing generating principle when grinding a helically toothed gear wheel by means of a doubly dished or doubly conical grinding wheel or a pair of singly dished or singly conical grinding wheels reciprocatable in grinding strokes along the gear tooth flanks, wherein the stroke motion is controlled in dependence of measured values of the generating motion and of the momentary position of the grinding wheel or wheel pair upon the gear tooth flank being ground.
A method of this type is described in the German Patent Publication No. 1,777,374, published Aug. 30, 1973, based upon the fact that in helically toothed gear wheels each individual tooth is curved in the form of a helix so that its flank surfaces cannot be swept or contacted over their entire length by a grinding body or wheel moving in a plane. The grinding body or wheel is therefore out of engagement during a portion of its stroke path; this portion is small in helical gearing having a large diameter and a small helix angle, but increases rapidly as the diameter decreases and the helix angle increases. In helically toothed gear wheels of usual size, the idle or ineffective path of the grinding body or wheel often amounts to the major portion of the entire stroke path and is often a multiple of the effective engagement path which is itself relatively small.
This known method therefore sets itself the object of controlling the stroke motion such that it is adapted to the momentary engagement path of the grinding body or wheel. According to the previously mentioned German Patent Publication No. 1,777,374, this object is to be fulfilled in that the magnitude and position of the stroke motion of the grinding machine ram follows or simulates the magnitude and momentary position of the effective engagement path of the grinding body or wheel upon the tooth flank being ground in dependence of the measured value of one of the components of the generating motion. How this is done in detail and why the measurement of one component of the generating motion is supposed to be sufficient is not disclosed.